Andy Coulson is portrayed in the book as a key figure during David Cameron’s first18 months in government and previously in his time as leader of the opposition.
Photograph: David Fisher/Rex Features

David Cameron ignored at least “three high-level warnings” about employing former News of the World editor Andy Coulson, including one from Daily Mail editor Paul Dacre, according to the full version of Lord Ashcroft’s unauthorised biography of the prime minister.

Extracts of the book published last month by the Daily Mail have already made a series of damaging claims about Cameron including involvement in a drug-taking environment at university, knowledge of Ashcroft’s offshore tax status, and his now infamous alleged involvement in a bizarre dinner club ritual involving a pig’s head.

Conservative sources said No 10 did not recognise any of the allegations made on the front page of the Daily Mail and later there was a specific denial of the pig’s head allegation.

The Daily Mail’s edited extracts omitted a claim that Dacre, its own editor-in-chief, warned Cameron against bringing Coulson into government as director of communications when the Tories were elected in 2010.

Coulson is portrayed in the book as a key figure during Cameron’s first months in government and previously in his time as leader of the opposition.

He resigned in January 2011, saying allegations that he was involved in phone hacking when editor of the News of the World made it impossible for him to continue. He was found guilty of conspiring to intercept voicemails in 2014 and jailed for 18 months, serving five.

Ashcroft’s book, which was co-written with the political journalist Isabel Oakeshott, says: “Cameron had come to rely on his clever director of communications. Convinced Coulson had known nothing of phone hacking (and presumably unaware that Coulson and [Rebekah] Brooks had been lovers), the prime minister ignored at least three high-level warnings about bringing him into government.”

It adds: “Among those who privately counselled against the move were Daily Mail boss Paul Dacre, who said it was ‘storing up trouble’, former Evening Standard editor Max Hastings, and his old family friend Nicholas Soames.”

In July 2011 Cameron told parliament that warnings from Alan Rusbridger, then Guardian editor, about Coulson’s fitness for a job in government – made to one of his most senior aides – were not relayed to him.

Soames is quoted saying: “I did make my views very strongly known about the employment of Coulson. I expressed it very strongly that, firstly, you can employ him as leader of the opposition, but you can’t employ him in Number 10. I made my feelings known both verbally and in writing.”

But the warnings were ignored. Soames went on: “David is dog loyal. And that’s great ... I think he and George [Osborne] both decided that Andy Coulson would be the best person.”

Brooks, the former Sun editor and News International chief executive, was left “deeply angry and upset” after Cameron “deserted” her in the wake of the phone-hacking scandal, the book claims.

And Cameron privately conceded that the then Labour leader, Ed Miliband, had him “on the run” over phone hacking, it says. It noted that he was widely seen to have panicked into announcing the Leveson inquiry into the scandal.

Cameron’s social circle in Oxfordshire, dubbed the Chipping Norton set, which included Brooks, was renamed the Upset in the wake of phone hacking, the book claims.

The prime minister’s inner circle emerges as a foul-mouthed bunch from a speed-reading of the book. There are 46 instances of “fuck”, “fucking” or “fucked” in the book, mostly in reported speech by Cameron’s aides and cabinet colleagues.

Miliband is described as “a fucking cunt and copper-bottomed shit” after leading a vote against intervention in Syria, a Number 10 source is quoted as saying in the book.

When Cameron’s future wife Samantha first started dating Cameron in the early 1990s, he was an adviser to the then chancellor, Norman Lamont. She told Cameron to tell Lamont to “fuck off”, according to the book.

But Cameron himself comes across as quaintly innocent of the language of those around him. The Australian election strategist Lynton Crosby, called Cameron a “posh cunt” when the two worked together on the ill-fated 2005 general election campaign. The first time Cameron was sent a “WTF” text by a Crosby, he did not have his glasses on and mistook the initials for the World Economic Forum, the book claims.

Sun editor says he would have published Cameron 'pig' serialisation

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It also claims that Cameron once tried to restrain his policy guru Steve Hilton when he looked as if was about to punch the then international development secretary Andrew Mitchell.

“He’s trying to help me Steve – let it go,” Cameron was quoted as saying at the time.

The book notes that Cameron has failed to deny using cocaine before he became a MP. “Voters are left to draw their own conclusions,” it says.

People have already made up their minds about allegations in the book, Cameron told BBC1’s Andrew Marr Show on Sunday.

He said: “I think everyone can see through it, so frankly I am not going to dignify it with individual responses. I think people have had a look and they have made their mind up.”

Ashcroft – who gave the Conservatives £8m while the party was in opposition and led a drive to win marginal seats – has said he decided to write the book when Cameron declined to reward him with a sufficiently senior job in government when he came to power in 2010.

Cameron told Marr: “I appoint people on merit, on their ability to do the job, and not on anything else.”

• This article was amended on 6 October 2015. A paragraph incorrectly claiming that Lord Ashcroft brought forward publication of the book has been deleted. He did not. Iain Dale, the publisher, made the decision to bring forward publication to 5 October when the printers told him it would be available to bookshops by 2 October.